Sensor module and method of manufacturing the same

ABSTRACT

The opto-electronic module ( 1 ) comprises —a first substrate member (P); —a third substrate member (B); —a second substrate member (O) arranged between said first and third substrate members and comprising one or more transparent portions (ta, tb) through which light can pass, said at least one transparent portion comprising at least a first optical structure ( 5   a;   5   a′;   5   b;   5   b ′); —a first spacer member (S 1 ) comprised in said first substrate member (P) or comprised in said second substrate member (O) or distinct from and located between these, which comprises at least one opening ( 4   a;   4   b ); —a second spacer member (S 2 ) comprised in said second substrate member (O) or comprised in said third substrate member (B) or distinct from and located between these, which comprises at least one opening ( 3 ); —a light detecting element (D) arranged on and electrically connected to said first substrate member (P); —a light emission element (E) arranged on and electrically connected to said first substrate member (P); —and a sensing element ( 8 ) comprised in or arranged at said third substrate member (B). Such modules ( 1 ) are particularly suitable as sensor modules for sensing a magnitude such as a pressure.

TECHNICAL FIELD

The invention relates to the field of sensors and sensing. Morespecifically, it relates to the packaging and manufacturing ofminiaturized sensor modules. More particularly, it relates toopto-electronic modules and to methods of manufacturing the same and toappliances and devices comprising such modules. The invention relates tomethods and apparatuses according to the opening clauses of the claims.

DEFINITION OF TERMS

“Active optical component”: A light sensing or a light emittingcomponent. E.g., a photodiode, an image sensor, an LED, an OLED, a laserchip. An active optical component can be present as a bare die or in apackage, i.e. as a packaged component.

“Passive optical component”: An optical component redirecting light byrefraction and/or diffraction and/or (internal and/or external)reflection such as a lens, a prism, a mirror, or an optical system,wherein an optical system is a collection of such optical componentspossibly also comprising mechanical elements such as aperture stops,image screens, holders.

“Opto-electronic module”: A component in which at least one active andat least one passive optical component is comprised.

“Replication”: A technique by means of which a given structure or anegative thereof is reproduced. E.g., etching, embossing, imprinting,casting, molding.

“Wafer”: A substantially disk- or plate-like shaped item, its extensionin one direction (z-direction or vertical direction) is small withrespect to its extension in the other two directions (x- andy-directions or lateral directions). Usually, on a (non-blank) wafer, aplurality of like structures or items are arranged or provided therein,typically on a rectangular grid. A wafer may have openings or holes, anda wafer may even be free of material in a predominant portion of itslateral area. A wafer may have any lateral shape, wherein round shapesand rectangular shapes are very common. Although in many contexts, awafer is understood to be prevailingly made of a semiconductor material,in the present patent application, this is explicitly not a limitation.Accordingly, a wafer may prevailingly be made of, e.g., a semiconductormaterial, a polymer material, a composite material comprising metals andpolymers or polymers and glass materials. In particular, hardenablematerials such as thermally or UV-curable polymers are interesting wafermaterials in conjunction with the presented invention, but semiconductormaterials, too.

“Lateral”: cf. “Wafer”

“Vertical”: cf. “Wafer”

“Light”: Most generally electromagnetic radiation; more particularlyelectromagnetic radiation of the infrared, visible or ultravioletportion of the electromagnetic spectrum.

BACKGROUND OF THE INVENTION

Sensors are widely used in physics, chemistry and in various fields ofengineering. Various magnitudes can be sensed using sensors, e.g.,pressure and temperature.

For various applications, it can be desirable to provide particularlysmall sensors. Furthermore, there is generally a demand for particularlyprecise and for particularly sensitive sensors.

SUMMARY OF THE INVENTION

One object of the invention is to create particularly miniscule orcompact or miniaturized opto-electronic module or sensor modules and/orto provide methods for manufacturing the same. Furthermore,corresponding appliances and devices shall be provided.

Another object of the invention is to provide a sensor module which ismass-producible, in particular on wafer scale.

Another object of the invention is to provide a particularly fast way ofmanufacturing sensor modules.

Another object of the invention is to provide a way of manufacturingsensor modules in a particularly small number of manufacturing steps.

Another object of the invention is to provide a sensor module having aparticularly high precision.

Another object of the invention is to provide a sensor module having aparticularly high sensitivity.

Another object of the invention is to provide a sensor module forsensing a magnitude while producing little effect only on the sensedmagnitude.

Another object of the invention is to provide a sensor module having aparticularly high degree of integration.

Further objects emerge from the description and embodiments below.

At least one of these objects is at least partially achieved byapparatuses and methods according to the patent claims.

The opto-electronic module comprises

-   -   a first substrate member;    -   a third substrate member;    -   a second substrate member arranged between said first and third        substrate members and comprising one or more transparent        portions through which light can pass, said at least one        transparent portion comprising at least a first optical        structure;    -   a first spacer member comprised in said first substrate member        or comprised in said second substrate member or distinct from        and located between these, which comprises at least one opening;    -   a second spacer member comprised in said second substrate member        or comprised in said third substrate member or distinct from and        located between these, which comprises at least one opening;    -   a light detecting element arranged on and electrically connected        to said first substrate member;    -   a light emission element arranged on and electrically connected        to said first substrate member;    -   a sensing element comprised in or arranged at said substrate        member.

Such opto-electronic modules can be efficiently manufacturable in highnumbers and may provide a high precision. Sensor modules can be realizedthis way, in particular sensor modules in which a contact-free read-outof changes occurring to said sensing element is accomplished.

Usually, said light emission element is provided for emitting light, inparticular for emitting light generally detectable by said lightdetecting element. And said light detecting element is usually providedfor detecting light, more particularly for detecting light emittable bysaid light emission element.

In a typical module, said second substrate member is distinct from saidfirst and third substrate members.

Said first and/or possible further optical structures are usuallyprovided for redirecting light, for guiding light, or for beam forming.

If said first spacer member is comprised in said first substrate member,it is usually located at an end of said first substrate member facingsaid second substrate member.

If said first spacer member is comprised in said second substratemember, it is usually located at an end of said second substrate memberfacing said first substrate member.

If said second spacer member is comprised in said second substratemember, it is usually located at an end of said second substrate memberfacing said third substrate member.

If said second spacer member is comprised in said third substratemember, it is usually located at an end of said third substrate memberfacing said second substrate member.

Any of said first or possible further optical structures can be, e.g., alens or lens element of spherical or aspherical or other type, or aprism or any diffractive and/or refractive optical structure.

In one embodiment, the module comprises a lens comprising said firstoptical structure, in particular wherein said lens comprises, inaddition, a second optical structure. Said second optical structure canbe, e.g., a diffractive and/or refractive optical structure, such a lenselement.

In one embodiment which may be combined with the before-addressedembodiment

-   -   said light emission element,    -   said one or more transparent portions,    -   said sensing element, and    -   said light detecting element        are mutually arranged such that light emitted by said light        emission element can propagate along a light path        interconnecting    -   said light emission element,    -   said one or more transparent portions,    -   said sensing element, and    -   said light detecting element.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said module is a sensor module for sensinga magnitude.

Said magnitude can be, e.g., at least one of a mechanical magnitude;

-   -   a pressure;    -   a temperature;    -   an electromagnetic magnitude;    -   a magnetic field strength;    -   an electric field strength    -   a reflectivity;    -   an optical absorption or attenuation;    -   a transmittivity.

In one embodiment of the sensor module, said sensing element issensitive to changes in said magnitude. It can be provided that saidsensing element is structured and configured such that when it isexposed to changes in said magnitude, a change concerning said sensingelement is caused. E.g., the amount or strength of said changeconcerning the sensing element can depend on said change in saidmagnitude.

E.g., said sensing element can be structured and configured such that itis deformable by changes in said magnitude. And, said sensing elementcan be structured and configured such that it is movable by changes insaid magnitude, wherein movable may comprise one or more of rotatable,tiltable, deplaceable.

It is possible to provide that said sensing element is structured andconfigured such that it changes its shape or position or orientation independence of said magnitude or in dependence of changes in saidmagnitude.

In one embodiment of the sensor module which may be combined with thebefore-addressed sensor module embodiment, said sensing elementcomprises at least one of

-   -   a micromechanical element;    -   an axis of rotation and a portion rotatable around said axis of        rotation;    -   a tilt axis and a portion tiltable about said tilt axis;    -   a deformable membrane;    -   a reflective or mirrored membrane;    -   an optical waveguide.

In case of an optical waveguide, that waveguide can in particularcomprise two diffraction gratings, for coupling light into and forcoupling light out of the waveguide. And the waveguide may comprise aface, where at the inside of the waveguide, light propagating inside thewaveguide may be totally internally reflected (in particular in order topropagate inside the waveguide from an input grating to an outputgrating), and where at the outside of the waveguide, an object orsubstance to be sensed may be present, e.g., be absorbed. This way, itis possible to achieve that, depending on properties of said object orsubstance (such as optical absorption properties, the position of theobject or substance and an amount of the object or substance present atsaid face), a property of the waveguide changes (such as itsreflectivity at said face) and, accordingly, a property of light havingpassed through the waveguide changes. E.g., in reaction to an absorptionof molecules of a certain species, a ratio of an intensity of lightexiting the waveguide and of an intensity of light fed into thewaveguide can decrease.

In one embodiment of the sensor module which may be combined with one ormore of the before-addressed sensor module embodiments, a change in saidmagnitude is detectable in said module via a change in light impingingon said light detecting element. More particularly, it can be providedthat said change in said magnitude is detectable in said module via achange in the location on said light detecting element at which lightimpinges on said light detecting element.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said sensing element comprises an at leastpartially reflective portion. Said at least partially reflective portionsubstantially may, e.g., be an at least partially reflective coating ora bulk optical element such as an optical mirror. Usually, said at leastpartially reflective portion faces said second substrate wafer.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said light detecting element is at leastone of

-   -   a one-dimensional light detector;    -   a two-dimensional light detector;    -   a position-sensitive light detector.

Generally, and this applies to all described embodiments, the detectionelement can be any light detector or light detector arrangement. Adetection element can detect or sense light; thus, it can also bereferred to as a light sensing element or as a light sensor. It can be atwo-dimensional light detector such as a multi-pixel image sensor, e.g.,in CMOS technology or a CCD device, or a one-dimensional light detectorsuch as a linear arrangement of photo diodes, or a zero-dimensionallight detector such as a single photo diode. The first type of detectionelements are considered to have spatial resolution (orposition-sensitivity) in two lateral directions, the latter in onelateral direction only, and the last to provide no spatial resolution(and no position-sensitivity). For various applications, one- ortwo-dimensional light detectors will be used rather thanzero-dimensional ones. Position sensitivity means, more specifically,that a corresponding detection element is capable of distinguishingbetween different locations of light incidence (on itself).

Said light detecting element may be, e.g., at least one of

-   -   a multi-pixel light detector;    -   a multi-pixel light detector of linear type;    -   a multi-pixel light detector of two-dimensional type;    -   an image detector, in particular of CMOS-type or of CCD type;    -   an arrangement of light detectors along a line, in particular        along a straight line;    -   a linear arrangement of photo diodes;    -   a two-dimensional arrangement of photo diodes.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said second substrate wafer comprises atleast one non-transparent blocking portion. It can, more specifically,be provided that each of said transparent portions is laterally enclosedby said at least one blocking portion

This blocking portion usually is provided for blocking a propagation oflight across the blocking portion, at least in case of light generallydetectable by the light detection element.

Accordingly, it can be provided that said optics wafer comprises atleast one portion, referred to as blocking portion, which is at leastsubstantially non-transparent for at least a specific wavelength range,and at least one other portion, namely a transparent portion, which isat least substantially transparent for at least said specific wavelengthrange.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said first spacer member comprises atleast a first and a second opening. These openings are usually separatefrom each other, in particular separated by a portion of the firstspacer wafer. This is particularly useful in case of modules with two ormore channels. E.g., said light emission element can be located withinor at said first opening and said light detecting element within or atsaid second opening. And, if present, it can also be provided that saidfirst transparent portion is located at said first opening and saidsecond transparent portion at said second opening.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said at least one opening in said firstspacer member is delimited and, in particular fully enclosed, by saidfirst and second substrate members and said first spacer member.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said at least one opening in said secondspacer member is delimited and, in particular fully enclosed, by saidthird and second substrate members and said second spacer member.

One or both of the last-addressed embodiments can be useful forrealizing optically and/or hermetically sealed modules or moduleportions. At least one or two or three or even more cavities can beformed in the module. In said cavities, one or more passive opticalcomponents and/or one or more active optical components may be present.In particular, the openings or cavities encased in the module may behermetically sealed. This may protect their respective insides fromdetrimental influences such as dust or dirt. Hence, optical componentsin the module can be protected this way, and light paths inside themodule remain in good condition for a long time.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments,

-   -   said first substrate member has a first face which is        substantially planar;    -   said third substrate member has a fourth face facing said first        face, which is substantially planar and is aligned substantially        parallel to said first face,    -   said second substrate member has a second face facing said first        face, which is substantially planar and is aligned substantially        parallel to said first face and a third face facing said fourth        face, which is substantially planar and is aligned substantially        parallel to said first face.

Typically, said light detecting element and said light emission elementare present on said first face. And also typically, said one or moreoptical structures are present on said second face and/or on said thirdface.

Note that directions perpendicular to said first face are referred to asvertical directions.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, by said first substrate member, at leastone electrical connection across the first substrate member is provided.More particularly, it can be provided that said first substrate membersubstantially is a printed circuit board or a printed circuit boardassembly.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said first, second and third substratemembers and said first and second spacer members are of generally block-or plate-like shape, possibly comprising at least one hole. Awafer-level manufacture of such modules may be well possible.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, outer bounds of a vertical silhouette ofthe module (i.e. the outer borders of a shape described by the module ina projection into a lateral plane) and outer bounds of a verticalsilhouette of said first, second and third substrate members and of saidfirst and second spacer members (i.e. the outer borders of a shapedescribed by the respective member in a projection into a lateral plane)each describe a substantially rectangular shape. This can effect anenhanced manufacturability. In particular, all of the mentioned verticalsilhouettes can describe one and the same rectangular shape. It can beprovided that lateral dimensions of all said members are substantiallyidentical. It is well possible to wafer-level manufacture such modules,which in turn can result in high-precision high-volume manufacturing.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, at least one of said first, second andthird substrate members and first and second spacer members, inparticular all of these, are, at least in part, made substantially of atleast substantially non-transparent material. Of course, said one ormore transparent portions are not made of an at least substantiallynon-transparent material. Such a choice of material can inhibitundesired exit of light out of the module and/or avoid that undesiredlight enters the module. It may contribute to optically sealing themodule, wherein the optical sealing may (locally) interrupted in theregion of the sensing element, in particular solely thereby.Accordingly, it may be provided that the first and the second substratemembers are substantially in full, except for said one or moretransparent portions, made substantially of an at least substantiallynon-transparent material. And also the third substrate members may besubstantially in full, possibly except for a region where said sensingelement is present, made substantially of an at least substantiallynon-transparent material. It may furthermore be provided that said firstand second spacer members are substantially in full made substantiallyof an at least substantially non-transparent material. Suitablenon-transparent materials may be, e.g., polymer materials. Said firstsubstrate member can be substantially (or at least predominantly) madeof a semiconductor material, more specifically of silicon, and,alternatively, it may be substantially (or at least predominantly) madeof a printed circuit base material such as polyimide or an FR4 material.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, at least one of said first and secondspacer members, in particular both, said first and said second spacermember, is at least one of made of a hardened hardenable material andobtained using a replication process. This can make possible to achievean enhanced manufacturability. And this can make possible to providespacer members in form of unitary parts in an efficient way and in highprecision. Hardening may be accomplished, e.g., by heating, inparticular if the respective spacer member is substantially made ofnon-transparent material.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, said second substrate member is, at leastin part, at least one of made of a hardened hardenable material andobtained using a replication process. In particular, at least said firstoptical structure can be, at least in part, at least one of made of ahardened hardenable material and obtained using a replication process.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, at least one of said first and secondspacer members, in particular both, said first and said second spacermember, is a unitary part. This may in particular be provided when oneor both of said spacer members is distinct from all said substratemembers.

Typically, one or both of said spacer members, in particular whendistinct from said substrate members, has a vertical extension which islimited to the vertical range from the above-mentioned first face to theabove-mentioned second face.

Generally, a spacer member, more particularly a separate (distinct)spacer member, can also be referred to as a distancing member, becauseit can effect a well-defined (vertical) distance between adjacentsubstrate members, more particularly between the respective faces.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, the module comprises a housing, saidhousing being, possibly except for a portion of said third substratemember comprising said sensing element, completely non-transparent, suchthat light can enter or exit an inside volume of the module, if at all,solely through said portion of said third substrate member, inparticular wherein said first, second and third substrate members andsaid first and second spacer members contribute to, and moreparticularly, make up for said housing. Said inside volume can inparticular be hermetically sealed.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, a maximum vertical extension of the moduleis at most 40 mm, in particular at most 25 mm.

In one embodiment which may be combined with one or more of thebefore-addressed embodiments, a maximum lateral extension of the moduleis at most 35 mm, in particular at most 20 mm.

The appliance comprises a multitude of opto-electronic modules of theabove-described kind. The appliance can in particular be a wafer stack.Such an appliance or wafer stack is particularly useful formass-producing above-described modules.

In one embodiment, the appliance comprises

-   -   a first substrate wafer comprising a multitude of said first        substrate members;    -   a second substrate wafer comprising a multitude of said second        substrate members;    -   a third substrate wafer comprising a multitude of said third        substrate members;    -   a first spacer wafer comprising a multitude of said first spacer        members, wherein said first spacer wafer is comprised in said        first substrate wafer or is comprised in said second substrate        wafer or is distinct from these;    -   a second spacer wafer comprising a multitude of said second        spacer members, wherein said second spacer wafer is comprised in        said third substrate wafer or is comprised in said second        substrate wafer or is distinct from these;    -   a multitude of said light detecting elements arranged on said        first substrate wafer;    -   a multitude of said light emission elements arranged on said        first substrate wafer; and    -   a multitude of said sensing elements comprised in or arranged at        said third substrate wafer.

In such an appliance, usually,

-   -   one of said light detecting elements;    -   one of said light emission elements;    -   one or more of said transparent portions and optical portions;    -   one of said sensing elements;        are allocated with each other. After a separation step, these        will belong to one and the same sensor module.

It is possible to provide that said first substrate wafer substantiallyis a printed circuit board or a printed circuit board assembly.

The method for manufacturing an opto-electronic module comprises thesteps of

-   a) providing a first substrate wafer on which a multitude of light    emission elements and a multitude of light detecting elements are    present;-   b) providing a second substrate wafer comprising a multitude of    transparent portions through which light can pass, at least a    plurality of said multitude of transparent portions comprising at    least a first optical structure each;-   c) providing a third substrate wafer, wherein a multitude of sensing    elements is comprised in or arranged at said third substrate wafer;-   d) providing a first spacer wafer comprised in said first substrate    wafer or comprised in said second substrate wafer or distinct from    these, which comprises a multitude of openings;-   e) providing a second spacer wafer comprised in said third substrate    wafer or comprised in said second substrate wafer or distinct from    these, which comprises a multitude of openings;-   f) forming a wafer stack comprising said first substrate wafer, said    second substrate wafer, said third substrate wafer, said first    spacer wafer and said second spacer wafer such that said second    substrate wafer is arranged between said first and said third    substrate wafers and that said first spacer wafer is arranged    between said first and said second substrate wafers and that said    second spacer wafer is arranged between said third and said second    substrate wafers.

This way, efficient mass-production of opto-electronic modules or sensormodules of high precision may be achieved.

In one method embodiment, in said wafer stack, each of said lightemission elements is allocated with an opening of said openings of saidfirst spacer wafer and with a transparent portion of said transparentportions, and each of said light detecting elements is allocated with anopening of said openings of said first spacer wafer and with atransparent portion of said transparent portions.

It is also possible to provide that, in said wafer stack, each of saidlight emission elements is located within an opening of said openings ofsaid first spacer wafer, and each of said light detecting elements islocated within an opening of said openings of said first spacer wafer.

In one embodiment which may be combined with one or more of the methodembodiments, the method comprises the step of

-   l) positioning each of said multitude of light emission elements    and/or each of said multitude of light detecting elements on said    first substrate member using a pick-and-place step.

In one embodiment which may be combined with one or more of thebefore-addressed method embodiments, the method comprises at least oneof the steps of

-   m1) manufacturing said first spacer wafer using replication, in    particular an embossing process;-   m2) manufacturing said second spacer wafer using a replication    process, in particular an embossing process.

In one embodiment which may be combined with one or more of thebefore-addressed method embodiments, the method comprises at least oneof the steps of

-   n) manufacturing said optical structures using a replication    process, in particular an embossing process.

In one embodiment referring to the last-addressed embodiment, step n)comprises the steps of

-   n1) depositing replication material, in particular on a precursor    wafer to become said second substrate wafer;-   n2) bringing a replication tool into contact with said replication    material;-   n3) hardening said replication material;-   n4) removing said replication tool.

In step n3), heat or UV radiation may be applied.

In one embodiment which may be combined with one or more of thebefore-addressed method embodiments, each of said sensing elementscomprises an at least partially reflective portion, said at leastpartially reflective portion usually facing said second substrate wafer.

In one embodiment which may be combined with one or more of thebefore-addressed method embodiments, the method comprises at least oneof the steps of

-   g) separating said wafer stack into said multitude of    opto-electronic modules.

Said separating may be accomplished using known dicing techniques, e.g.,sawing, laser cutting and others. It can be provided that each of saidopto-electronic modules is an opto-electronic module of theabove-described kind.

The invention comprises modules with features of corresponding methodsaccording to the invention, and, vice versa, also methods with featuresof corresponding modules according to the invention.

The advantages of the modules basically correspond to the advantages ofcorresponding methods, and, vice versa, the advantages of the methodsbasically correspond to the advantages of corresponding modules.

Furthermore, a method for manufacturing a device is provided. The methodfor manufacturing the device, said device comprising an opto-electronicmodule, comprises manufacturing said opto-electronic module according toone of the above-described methods, in particular wherein saidopto-electronic module is an opto-electronic module of theabove-described kind.

In particular, the device can be a sensor or a communication device suchas a smart phone, it can be a hand-held device and/or a mobile computingdevice.

The device according to the invention comprises a module of theabove-described kind, in particular wherein said device comprises aprinted circuit board to which said module is operationally connected.Possible kinds of devices have been mentioned above. However, the devicecan in particular be an electronic device; it can in particular be asensor; the device can also be a mobile and/or hand-held device; it canbe a communication device such as a smart phone.

In a particular aspect of the invention, the invention comprises aparticular sensor module for sensing a magnitude: That sensor modulecomprises a sensing element and an optical read-out arrangement fordetecting changes of said sensing element, wherein said optical read-outarrangement comprises

-   -   a first substrate member;    -   a light detecting element and a light emission element, both        arranged on and electrically connected to said first substrate        member;    -   a second substrate member arranged between said first substrate        member and said sensing element, comprising one or more        transparent portions through which light can pass, said at least        one transparent portion comprising at least a first optical        structure; and    -   a first spacer member comprised in said first substrate member        or comprised in said second substrate member or distinct from        and located between these, which comprises at least one opening.

As is readily understood, various of the features of the opto-electronicmodules described further above can be present also in such a sensormodule and more particularly in the optical read-out arrangement. Theseare, with some exceptions, not repeated here.

In one embodiment of the sensor module, said light detecting element isat least one of

-   -   a one-dimensional light detector;    -   a two-dimensional light detector;    -   a position-sensitive light detector.

In one embodiment which may be combined with the before-addressed sensormodule embodiment, said sensing element is sensitive to changes in saidmagnitude. The sensing element may, e.g., be subject to changes in itsposition and/or its shape in reaction to changes in said magnitude.

Further embodiments and advantages emerge from the dependent claims andthe figures.

BRIEF DESCRIPTION OF THE DRAWINGS

Below, the invention is described in more detail by means of examplesand the included drawings. The figures show in a strongly schematizedmanner:

FIG. 1 a cross-sectional view of an opto-electronic module embodying asensor module having a membrane;

FIG. 2 various cross-sectional views of constituents of the module ofFIG. 1;

FIG. 3 a cross-sectional view of wafers for forming a wafer stack formanufacturing a multitude of modules of FIG. 1;

FIG. 4 a cross-sectional view of a wafer stack for manufacturing amultitude of modules of FIG. 1;

FIG. 5 across-sectional view of an opto-electronic module embodying asensor module having a rotatable sensing element;

FIG. 6 a sensor substrate member in a cross-sectional view;

FIG. 7 a sensor substrate member in a cross-sectional view.

The described embodiments are meant as examples and shall not confinethe invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a cross-sectional view of an opto-electronic module 1embodying a sensor module having a sensing element 8 which is embodiedas a membrane. At the same time, FIG. 1 illustrates a device 10comprising such a module 1.

The illustrated cross-section is a vertical cross-section. FIG. 2 showsvarious lateral schematic cross-sectional views of constituents of themodule of FIG. 1, wherein the approximate positions of these lateralcross-sections are indicated in FIG. 1 by s0 to s5 and dashed lines. Fors4 and s5, the direction of view is indicated by arrows.

Device 10 can be, e.g., an electronic device and/or a sensor device. Itmay be, e.g., a hand-held communication device such as a smart phone.Module 1 is particularly suitable for such applications because it canbe manufactured having a particularly small size and it ismass-producible using wafer-level manufacturing techniques. Device 10comprises, besides module 1, a printed circuit board 9 on which module 1is mounted. In addition mounted on printed circuit board 9 is anintegrated circuit c such as a control unit or controller chip which isoperationally interconnected with module 1 by printed circuit board 9.E.g., integrated circuit c may evaluate signals outputted by module 1and/or provide signals to module 1 for controlling the same.

Module 1 comprises several constituents (P, S1, O, S2, B) stacked uponeach other in a direction through which the term “vertical” is defined;it corresponds to the z direction (cf. FIG. 1). Directions in the x-yplane (cf. FIG. 2) perpendicular to the vertical (z) direction arereferred to as “lateral”.

Module 1 comprises a first substrate member P, a first spacer member S1,a second substrate member O, also referred to as optics member O, asecond spacer member S2 and a third substrate member B, also referred toas sensor substrate member B, all stacked upon each other. The memberscomprise faces F0, F1, F2, F3, F4 and F5 as indicated in FIG. 1.Substrate member P is, e.g., a printed circuit board assembly. Theprinted circuit board (PCB) of this PCB assembly can more specificallyalso be referred to as an interposer. On the PCB, a light emissionelement E for emitting light, e.g., infrared light or visible light, ismounted. This can be, e.g., a light-emitting diode or a laser diode, inparticular a VCSEL (vertical-cavity surface-emitting laser).Furthermore, a light detecting element D is mounted on substrate memberP, for detecting light, in particular light emittable by light emissionelement E. This can in particular be, e.g., an image detector or aone-dimensional detector such as a linear array of photo diodes.

Electrical contacts of light emission element E and light detectingelement D are electrically connected (across substrate member P) to theoutside of module 1, where solder balls 7 are attached. Instead ofproviding solder balls 7, it would also be possible to provide contactpads on the PCB which are not (or at a later time) provided with solderballs.

This way, module 1 can be mounted on a printed circuit board 9, e.g., insurface mount technology (SMT), next to other electronic components,such as integrated circuit c.

Spacer member S1 has two openings 4 a,4 b, light emission element Earranged in one of them (4 a) and light detecting element D beingarranged in the other (4 b). This way, light emission element E andlight detecting element D are laterally encircled by separating memberS1, and two separate channels are formed in module 1, in particular twooptically separate channels in the space between substrate members P andO.

Spacer member S1 may fulfill several tasks. It can ensure a well-defineddistance between substrate member P and optics member O (through itsvertical extension) which can help to achieve well-defined light pathsfrom emitting member E through optics member O (through transparentportion ta) and from opening 3 through optics member O (via transparentportion tb) onto light detecting element D. Therefore, spacer member S1can also be referred to as a separation member (separation member S1).Spacer member S1 can also provide protection of light detecting elementD from light that is not supposed to be detected by detection element D,by being substantially non-transparent to light generally detectable bylight detecting element D and by forming a portion of the outside wallsof module 1. And, spacer member S1 can also provide protection of lightdetecting element D from light emitted by emitting member E which shouldnot reach light detecting element D, so as to reduce optical cross-talkbetween light emission element E and detecting member D, by beingsubstantially non-transparent to light (in particular to light generallydetectable by light detecting element D) and by forming a wall (or:channel separator) between light emission element E and light detectingelement D. Light reflected inside module 1 and stray light originatingfrom light emission element E can be kept from reaching light detectingelement D this way. Typically, separating member S1 is made of a polymermaterial, in particular of a hardenable or more specifically curablepolymer material, e.g., of an epoxy resin.

Optics member O comprises a blocking portion b and two transparentportions ta and tb, respectively, one (ta) for allowing light emitted bylight emission element E to leave opening 4 a and enter opening 3, andanother one (tb) for allowing light to enter opening 4 b from opening 3and reach light detecting element D.

Transparent portions ta, tb each comprise a passive optical component Laand Lb, respectively, more particularly and as in the illustratedexample, a lens member each, for light guidance and/or beam forming.Lens members La, Lb may, e.g., comprise, as shown in FIG. 1, two lenselements 5 a, 5 a′ and 5 b, 5 b′, respectively, in close contact to atransparent element 6 a and 6 b, respectively. Transparent elements 6 a,6 b can have the same vertical dimension as optics member O where itforms blocking portion b, such that optics member O where it formsblocking portion b together with transparent elements 6 describes a(close-to-perfect) solid plate shape. Lens elements 5 a, 5 a′, 5 b, 5b′, redirect light by refraction (cf. FIG. 1) and/or by diffraction (notillustrated). E.g., they may all be of generally convex shape (as shownin FIG. 1), but one or more of the lens elements may be differentlyshaped, e.g., generally or partially concave. Lens elements 5 a′, 5 b′may be, e.g., aspherical lens elements, as illustrated in FIG. 1.

Spacer member S2 has one opening 3 which laterally encircles a volumepresent between substrate members B and O.

Spacer member S2 may fulfill several tasks. It can ensure a well-defineddistance between substrate member B and optics member O (through itsvertical extension) which can help to achieve well-defined light pathsbetween sensing element 8 and each of the transparent portions to andtb. Therefore, spacer member S2 can also be referred to as a separationmember (separation member S2).

Spacer member S2 can also provide protection against light entering thebefore-mentioned volume that is not supposed to enter that volume,namely by being substantially non-transparent to light (at least tolight generally detectable by light detecting element D) and by forminga portion of the outside walls of module 1. Typically, separating memberS2 is made of a polymer material, in particular of a hardenable or morespecifically curable polymer material, e.g., of an epoxy resin.

Substrate member B is, at least predominantly, made of a non-transparentmaterial such as a non-transparent polymer material. This is the case atleast in the region where sensing element 8 is not present.

The volumina laterally enclosed by spacer members S1,S2 can inparticular be hermetically sealed, which not only prevents dust or otherparticles from degrading optical properties, but also contributes to thepossibility of measuring pressures using module 1. For the latterpurpose, sensing element 8 basically is a membrane deforming uponexperiencing different pressures on its opposite sides, i.e. differentpressures between the regions present adjacent to faces F4 and F5,respectively, of member B. The membrane may be made of, e.g., asilicone, bonded to member B.

Inside and by means of module 1, deformations of the membrane can bedetected or monitored in a contact-free manner, using light. On thatside of the membrane which faces towards optics member O, sensingelement 8 has a reflective portion 8 r. Reflective portion 8 r may beembodied by a coating present on sensing element 8, or by a mirrorattached to sensing element 8. Light emitted by light emission element Ehaving passed transparent region ta will be reflected by reflectiveportion 8 r in different ways, depending on the deformation of themembrane and thus depending on a pressure to be sensed. Thus, the lightpath along which the light travels from reflective portion 8 r throughtransparent portion tb to detection element D and the location ondetection element D where the light finally impinges on detectionelement D depends on the pressure to be sensed. Accordingly, themagnitude to be sensed, i.e., in the illustrated embodiment, thepressure, can be deduced from that location on detection element D. Withdetection element D having position sensitivity, this is readilyaccomplished. Typically after some gauging, a corresponding pressurevalues can be obtained, e.g., by means of integrated circuit c.

Such a module 1 may thus be a pressure sensor module.

The lateral shape of openings 3, 4 a and 4 b and also of transparentportions ta, tb may, e.g., be circular or have other appearances, e.g.,polygonal or rectangular with rounded corners.

Module 1 is an opto-electronic component, more precisely a packagedopto-electronic component. The vertical side walls of module 1 areformed by items P, S1, S2, O and B. A bottom wall is formed by substratemember P, and a top wall by sensor substrate member B.

As is well visible in FIG. 2, the five items P, S1, S2, O, B, which canfor the reasons above also be referred to as housing components, allhave substantially the same lateral shape and lateral dimensions. Thisis related to a possible and very efficient way of manufacturing suchmodules 1 which is described in more detail below referring to FIGS. 3and 4. These housing components P, S1, S2, O, and B are all of generallyblock- or plate-like shape or more generally of generally rectangularparallelepiped shape, possibly having holes or openings (such as spacermembers S1, S2 do) or projections (such as optics member O does).

It is furthermore possible to provide modules which are designedaccording to the same principles as discussed above, but comprising oneor more additional electronic components such as one or more additionalactive optical components, e.g., light detectors or light sources; orone or more integrated circuits. Additional passive optical componentsmay be provided as well.

The active electronic components comprised in a module (such as lightemission element E and light detecting element D in the example ofFIG. 1) can be packaged or unpackaged electronic components. Forcontacting substrate member P, technologies such as wire-bonding or flipchip technology or any other known surface mount technologies may beused, or even conventional through-hole technology.

FIG. 3 shows a schematical cross-sectional view of wafers for forming awafer stack for manufacturing a multitude of modules 1 as shown inFIG. 1. It is possible to manufacture such modules 1 (practically)completely on wafer-scale, of course with a subsequent separation step.Although FIGS. 3 and 4 only show provisions for three modules 1, therewill usually be in one wafer stack provisions for at least 10, rather atleast 30 or even more than 50 modules in each lateral direction. Typicaldimensions of each of the wafers are: laterally at least 5 cm or 10 cm,and up to 30 cm or 40 cm or even 50 cm; and vertically (measured with nocomponents arranged on substrate wafer PW) at least 0.2 mm or 0.4 mm oreven 1 mm, and up to 6 mm or 10 mm or even 20 mm.

Five wafers are sufficient for manufacturing a multitude of modules asshown in FIG. 1: A substrate wafer PW, two spacer wafers SW1 and SW2, anoptics wafer OW and a sensor wafer BW. Each wafer comprises a multitudeof the corresponding members comprised in the corresponding module 1(cf. FIGS. 1 and 2), usually arranged on a rectangular lattice,typically with a little distance from each other for a wafer separationstep.

Substrate wafer PW can be a PCB assembly comprising a PCB of standardPCB materials, provided with solder balls 7 on the one side and withactive optical components (E and D) soldered to the other side. Thelatter can be placed on substrate wafer PW by pick-and-place usingstandard pick-and-place machines.

In order to provide maximum protection from detecting undesired light,all wafers PW, SW1, SW2, OW, BW can substantially be made of a materialsubstantially non-transparent for light detectable by detecting membersD, of course except for transparent areas such as transparent portionsta, tb and openings 3, 4 a, 4 b.

Wafers SW1 and SW2 and possibly also all or a portion of wafers OW andBW can be produced by replication. In an exemplary replication process,a structured surface is embossed into a liquid, viscous or plasticallydeformable material, then the material is hardened, e.g., by curingusing ultraviolet radiation or heating, and then the structured surfaceis removed. Thus, a replica (which in this case is an negative replica)of the structured surface is obtained. Suitable materials forreplication are, e.g., hardenable (more particularly curable) polymermaterials or other replication materials, i.e. materials which aretransformable in a hardening step (more particularly in a curing step)from a liquid, viscous or plastically deformable state into a solidstate. Replication is a known technique, cf., e.g., WO 2005/083789 A2for more details about this.

In case of optics wafer OW, replication or molding may be used forobtaining the non-transparent portions (blocking portions b). It wouldalso be possible to provide holes, where transparent portions ta, tb aresupposed to be, by drilling or by etching.

Subsequently, a so-obtained precursor wafer is provided with passiveoptical components La, Lb, so as to yield optics wafer OW. This may beaccomplished by means of replication, e.g., forming lens members La, Lbas a unitary parts, e.g., as described in US 2011/0043923 A1. The lensmembers La, Lb can, however, also be manufactured starting from asemi-finished part being a wafer comprising transparent elements 6within holes by which transparent portions ta, tb are defined. This canbe particularly useful when the lens members La, Lb each describe atleast one apex, and those apices are located outside a verticalcross-section of the optics wafer OW. Such a semi-finished part is(usually, and in the exemplary case shown in the figures) a flatdisk-like wafer having no holes penetrating the wafer (in the regionswhere the transparent portions ta, tb shall later on be) and havingvirtually no or only shallow surface corrugations, such surfacecorrugations usually being concave, i.e. not extending beyond the wafersurface as described by the blocking portions b.

A semi-finished part like that can be obtained starting from a flatprecursor wafer (typically made of exactly one material) having holes oropenings where the transparent portions are supposed to be and thenfilling the holes with transparent material, e.g., using a dispensingprocess, and either filling the holes in the precursor wafer one-by-one,e.g., using a dispenser such as used for underfilling processes inflip-chip technology or the like, or by filling several holes at once,e.g., using a squeegee process (e.g. as known from screen printing) or adispenser with several hollow needles outputting material. During thedispensing, the wafer can be placed on a flat support plate, e.g., madeof a silicone. Care has to be taken order to prevent the formation ofair bubbles or cavities in the dispensed material, since this woulddegrade the optical properties of the lens members La, Lb to beproduced. E.g., one can carry out the dispensing in such a way thatwetting of the wafer material starts at an edge formed by the wafer andan underlying support plate (or in a place close to such an edge), e.g.,by suitably guiding a hollow needle outputting the material close tosuch an edge. Subsequently, the dispensed material is cured, e.g., byheat or UV radiation, so as to obtain hardened transparent material.

Convex meniscuses possibly formed this way can be flattened bypolishing, so as to obtain transparent elements 6 having parallelsurfaces adjusted to the wafer thickness. Then, by means of replication,lens elements 5 a, 5 a′, 5 b, 5 b′ are applied to typically both sides(top and button side) of wafer OW, e.g., using replication, inparticular embossing. In case of concave meniscuses of the transparentelements, the replication can take place on these, wherein the amount ofapplied replication material might have to be adjusted accordingly.

As has already been mentioned, it is generally possible to provide thatsaid spacer wafers SW1 and/or SW2 are obsolete in the sense that aparticular kind of optics wafer, a particular kind of sensor waferand/or a particular kind of substrate wafer is provided. Namely a wafer(“combined optics wafer” or “combined sensor wafer” or “combinedsubstrate wafer”) which incorporates the features and functionalities ofthe respective spacer wafer and the respective other wafer. Producingsuch a “combined wafer” may be accomplished using a particular precursorwafer and, manufactured based thereon, a particular semi-finished part.Such a precursor wafer and semi-finished part, respectively, has atleast one structured surface, usually having protrusions extendingvertically beyond at least one of the two surfaces of transparentelements to be provided in the precursor wafer and present in thesemi-finished part, respectively. Looking upon wafers OW and SW1 (or,e.g., wafers OW and SW2, or wafers BW and SW2, or wafers OW and SW1 andSW2) in FIG. 4 as one single part, it can be readily visualized what acorresponding “combined wafer” for manufacturing a module according toFIG. 1 and also a corresponding semi-finished part would look like.

In order to form a wafer stack 2, the wafers are aligned and bondedtogether, e.g., by gluing, e.g., using a heat-curable epoxy resin. It isusually a critical point to ensure that each active optical component(such as detecting members D and emission elements E on the substratewafer PW) is sufficiently accurately allocated with a correspondingpassive optical component (such as lens members La, Lb of optics waferOW).

FIG. 4 shows a cross-sectional view of a so-obtained wafer stack 2 formanufacturing a multitude of modules 1 as shown in FIG. 1. The thindashed rectangles indicate where separation takes place, e.g., by meansof using a dicing saw.

The fact that most alignment steps are carried out on wafer level makesit possible to achieve a good alignment (in particular of members D andE with respect to members La, Lb and all of these with respect tosensing element 8) in a rather simple and very fast way. The overallmanufacturing process is very fast and precise. Due to the wafer-scalemanufacturing, only a very small number of production steps is requiredfor manufacturing a multitude of modules 1.

FIG. 5 is a cross-sectional view of an opto-electronic module 1embodying a sensor module having a rotatable sensing element 8. Thismodule 1 is similar to the one of FIG. 1, but it comprises a differentsensing element 8, and differently designed transparent portions ta, tb.In contrast to the embodiment of FIG. 1, the optical structures (items 5a, 5 b, 5 b′) present in the transparent portions ta, tb are not lenselements, but prisms, and, accordingly, unlike in the embodiment of FIG.1, the passive optical components La, Lb are no lens members.

The sensing element 8 in the embodiment of FIG. 5 is tiltable orrotatable, about an axis A. Sensing element 8 can in particular comprisea plate-shaped part rotatably (or tiltably) mounted to member B, and theplate-shaped part can be a mirror or can be provided with a reflectivecoating, so as to embody a reflective portion 8 r. A magnitudeinteracting with sensing element 8 so as to cause a tilting of theplate-shaped part about axis A, be it a mechanical or an electrical ormagnetic magnitude or force, can thus be sensed by module 1, basicallyby evaluating where light initially emitted by light emission element Eimpinges on light detection element D.

FIG. 6 illustrates a sensor substrate member B in a cross-sectional viewwhich can be used as an alternative in the module 1 of FIG. 5. Thismember B provides mechanical stops for the rotation or tilting ofsensing element 8. Also this sensor substrate member B (without sensingelement 8) is well manufacturable using replication.

Following the described principles and ideas, various types of sensingmodules and sensors can be constructed. Miniscule mass-produciblehigh-precision sensing modules can be created along these lines.

FIG. 7 illustrates a sensor substrate member B in a cross-sectional viewwhich can be used in module 1, e.g., in the one of FIG. 1 or of FIG. 5.This member B provides an optical waveguide as sensing element 8. Theoptical waveguide has two parallel faces Fa, Fb at which total internalreflection can take place inside the waveguide and comprises an inputgrating g1 for coupling light into the waveguide (in particular lightoriginating from a light emission element E, cf. FIGS. 1 and 5) and aninput grating g2 for coupling light out of the waveguide. If, forexample, an object touches face Fb or a substance comes into contactwith face Fb or absorbs at face Fb, optical properties of the waveguidecan change. E.g., an amount of light exiting the waveguide can reduce,or a spectral composition of light exiting the waveguide can change, ora location where at the waveguide (or where at grating g2) light exitsthe waveguide can change. Any such change may then be detected, e.g., bymeans of light detecting element D.

The invention claimed is:
 1. A sensor module for sensing a magnitude,the module being an opto-electronic module comprising a first substratemember; a third substrate member; a second substrate member arrangedbetween said first and third substrate members and comprising at least afirst and a second transparent portion through which light can pass andat least one blocking portion, wherein each of said transparent portionsis surrounded laterally by said at least one blocking portion in a planeperpendicular to a stacking direction of the substrate members, andwherein said transparent portions comprise at least a first opticalstructure; a second spacer member comprised in said second substratemember or comprised in said third substrate member or distinct from andlocated between these, which comprises at least one opening; a lightdetecting element arranged on and electrically connected to said firstsubstrate member; a light emission element arranged on and electricallyconnected to said first substrate member; a sensing element comprised inor arranged at said third substrate member, wherein said sensing elementis sensitive to changes in said magnitude; and a first spacer membercomprised in said first substrate member or comprised in said secondsubstrate member or distinct from and located between these, whichcomprises at least a first and a second opening which are separated fromeach other by a portion of the first spacer member, wherein the at leastone blocking portion is non-transparent to light detectable by the lightdetecting element, and wherein the first spacer member is, at least inpart, non-transparent to light detectable by the light detecting elementto reduce optical cross-talk between the light emission element and thelight detecting element.
 2. The module according to claim 1, whereinsaid first optical structure is a lens or a lens element; or the modulecomprises a lens comprising said first optical structure.
 3. The moduleaccording to claim 1, wherein said light emission element, said one ormore transparent portions, said sensing element, and said lightdetecting element are mutually arranged such that light emitted by saidlight emission element can propagate along a light path interconnectingsaid light emission element, said one or more transparent portions, saidsensing element, and said light detecting element.
 4. The moduleaccording to claim 1, wherein said magnitude is at least one of amechanical magnitude; a pressure; a temperature; an electromagneticmagnitude; a magnetic field strength; an electric field strength areflectivity; an optical absorption or attenuation; or a transmittivity.5. The module according to 1, wherein said sensing element is structuredand configured such that it is deformable by changes in said magnitude.6. The module according to 1, wherein said sensing element is structuredand configured such that it is movable by changes in said magnitude. 7.The module according to claim 1, wherein said sensing element comprisesat least one of a micromechanical element; an axis of rotation and aportion rotatable around said axis of rotation; a tilt axis and aportion tiltable about said tilt axis; a deformable membrane; areflective or mirrored membrane; or an optical waveguide.
 8. The moduleaccording to claim 1, wherein a change in said magnitude is detectablein said module via a change in light impinging on said light detectingelement.
 9. The module according to claim 1, wherein said sensingelement comprises an at least partially reflective portion.
 10. Theaccording to claim 1, wherein said light detecting element is at leastone of a one-dimensional light detector; a two-dimensional lightdetector; or a position-sensitive light detector.
 11. The moduleaccording to claim 1, wherein said first substrate member has a firstface which is substantially planar; said third substrate member has afourth face facing said first face, which is substantially planar and isaligned substantially parallel to said first face; and said secondsubstrate member has a second face facing said first face, which issubstantially planar and is aligned substantially parallel to said firstface and a third face facing said fourth face, which is substantiallyplanar and is aligned substantially parallel to said first face.
 12. Themodule according to claim 1, wherein by said first substrate member, atleast one electrical connection across the first substrate member isprovided.
 13. The module according to claim 1, wherein said first,second and third substrate members and said first and second spacermembers are of generally block- or plate-like shape, comprising at leastone hole or comprising no hole.
 14. The module according to claim 1,wherein outer bounds of a vertical silhouette of the module and outerbounds of a vertical silhouette of said first, second and thirdsubstrate members and of said first and second spacer members eachdescribe a substantially rectangular shape.
 15. The module according toclaim 1, wherein at least one of said first substrate member, saidsecond substrate member, said third substrate member, said first andsecond spacer members is, at least in part, made substantially of atleast substantially non-transparent material.
 16. The module accordingto claim 1, wherein at least one of said first and second spacer membersis at least one of made of a hardened hardenable material and obtainedusing a replication process.
 17. The module according to claim 1,wherein said second substrate member is, at least in part, at least oneof made of a hardened hardenable material and obtained using areplication process.
 18. The module according to claim 1, wherein atleast one of said first or second spacer members is a unitary part. 19.An appliance comprising a multitude of sensor modules according toclaim
 1. 20. The appliance according to claim 19, comprising a firstsubstrate wafer comprising a multitude of said first substrate members;a second substrate wafer comprising a multitude of said second substratemembers; a third substrate wafer comprising a multitude of said thirdsubstrate members; a first spacer wafer comprising a multitude of saidfirst spacer members, wherein said first spacer wafer is comprised insaid first substrate wafer or is comprised in said second substratewafer or is distinct from these; a second spacer wafer comprising amultitude of said second spacer members, wherein said second spacerwafer is comprised in said third substrate wafer or is comprised in saidsecond substrate wafer or is distinct from these; a multitude of saidlight detecting elements arranged on said first substrate wafer; amultitude of said light emission elements arranged on said firstsubstrate wafer; and a multitude of said sensing elements comprised inor arranged at said third substrate wafer.
 21. A device comprising asensor module according to claim 1, wherein the device comprises aprinted circuit board to which said module is operationally connected.22. The module according to claim 1 wherein said first transparentportion is located at said first opening, and said second transparentportion is located at said second opening.
 23. The module according toclaim 1 wherein said light emission element is located within or at saidfirst opening and said light detecting element is located within or atsaid second opening.
 24. A sensor module for sensing a magnitude, thesensor module comprising a sensing element which is sensitive to changesin said magnitude and an optical read-out arrangement for detectingchanges of said sensing element, wherein said optical read-outarrangement comprises a first substrate member; a light detectingelement and a light emission element, both arranged on and electricallyconnected to said first substrate member; a second substrate memberarranged between said first substrate member and said sensing element,comprising at least a first and a second transparent portion throughwhich light can pass and at least one blocking portion, wherein each ofsaid transparent portions is laterally surrounded by said at least oneblocking portion in a plane perpendicular to a stacking direction of thesubstrate members, and wherein said transparent portions comprise atleast a first optical structure; and a first spacer member comprised insaid first substrate member or comprised in said second substrate memberor distinct from and located between these, which comprises at least afirst and a second opening which are separated from each other by aportion of the first spacer member, wherein the at least one blockingportion is non-transparent to light detectable by the light detectingelement, and wherein the first spacer member is, at least in part,non-transparent to light detectable by the light detecting element toreduce optical cross-talk between the light emission element and thelight detecting element.
 25. The sensor module according to claim 24,wherein said light detecting element is at least one of aone-dimensional light detector; a two-dimensional light detector; or aposition-sensitive light detector.
 26. A device comprising a sensormodule according to claim 24, wherein the device comprises a printedcircuit board to which said module is operationally connected.